Crankshaft grinding machine



June 6; 1939.

' w. H. w ooD CRANKSHAFT GRINDING MACHINE 2 She ets-Sheet 1 Filed Nov.. 18 1937 l VALLxurui H. W001:

I Patented June 6, 1939 UNlTE-D STATES CRANKSHAFT GRINDING MACHINE Wallace H. Wood, Wore ester, Mass, assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application November 18, 1937, Serial No. 175,295

Claims.

This invention relates to grinding machines, and more particularly to a machine for grinding the bearings of a crankshaft.

One object'of the invention is to provide a 5 simple, thoroughly practical grinding machine in which a manually operable control lever serves to control a hydraulic wheel feeding mechanism and an electrical drive for the work piece. Another object of the invention is to provide a control mechanism for a grinding machine in which a single lever is operatively connected so that when moved in one direction, it serves to control a hydraulic wheel feeding mechanism and when moved in the other direction serves to con-' trol stopping and starting of the work rotation. A further object of the invention is to provide an electrical control apparatus for a grinding machine in which an electrical control apparatus including a manually operable push button serves 0 to cause a reverse feeding movement of the grinding wheel and a stopping of the work rotation thereafter. t

This invention accordingly consists in the features of construction, combinations of elements,

and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indi-' cated in the following claims.

In the accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of this invention,

.Fig. 1 is a front elevation of the improved crankshaft bearing grinding machine;

Fig. 2 is a transverse sectional view taken approximately on the line2-2 of Fig. 1, on an enlarged scale, showing the wheel slide and the drive for the grinding wheel in elevation;

Fig; 3 illustrates a sectional view through the control lever mechanism combined with an electrical wiring diagram showing the control for the work driving motor and the solenoid for electrically reversing the wheel feed motor;

Fig. 4 is a fragmentary cross-sectional view, on an enlarged scale, taken approximately on the line 4-4 of Fig. 1, showing the control lever mechanism and its operating parts;

Fig. 5 is a fragmentary sectional view, on an enlarged scale, of the lower part of Fig. 4;

Fig. 6 is a fragmentary horizontal sectional view, taken approximately on the line 6-6 of Fig. 5, of the latch mechanism for controlling the work rotation; and

Fig. 7 is a diagrammatic view showing the various operating positions of the control lever.

- 5 As illustrated in the drawings, the machine embodying this invention comprises a base II) which supports a longitudinally reciprocable work supporting table II on the usual V-way l2 and flat way I3 for a longitudinal reciprocating movement relative to the base III. A motor driven headstock I4 and a footstock I5 are adjustably mounted on the swivel table 26 clamped on the table I I and are arranged rotatably to support a work piece, such as a crankshaft IS, on a headstock center I! and a footstock center m I8in operative relation with a rotatable grinding wheel l9.

The grinding wheel I 9 is rotatably supported on a wheel slide 28 of the usual type, such as shown in my prior U. S. Patent No. 2,071,677 5 dated February 23, 1937. The grinding wheel I9 may be rotated by an electric motor 2I mounted on the wheel slide 20. The motor 2| is provided with a pulley 22 which is connected by a multiple V-belt 23 with apulley '24 on the end of a 20 Wheel spindle 25. A

A fluid pressure mechanism is provided to reciprocate the work table II. In the form illustrated, a cylinder 30 is fixedly mounted to the under side of the table II. The details of the 25 table traverse mechanism have not been shown in detail since. they are not considered to be an essential part of the present invention. I For further details of construction as -to the hydraulic. table traverse mechanism, reference may be had 0 to my prior U. S. Patent No. 2,071,677 dated February 23, 1937.

A hollow box-like sump or reservoir 35 is formed in the base III and serves as a fluid reservoir for the pressure system. Fluid is drawn as from the reservoir 35 through a pipe 36, by a motor driven pump 31, and is forced through a pipe 38 and a pipe 39 to a table control valve 40.

A pressure relief valve 4| is provided in the pipe 38 and is arranged to allow fluid under pressure to by-pass through a pipe 42 and return to the reservoir 35 in case the pressure within the system increases above a desired pressure.

The control valve 40 comprises a reversing valve and a speed control or throttle valve, the 45 details of whichwill not be described since reference may be had to my prior patent above referred to for details of valve construction.

A reversing lever 50 is fixedly mounted on a pivotally mounted shaft 5| on the front of the 50 machine base III. The reversing lever 50 is arranged to be actuated by a pair of adjustable table dogs 52 and 53 which are adjustably sup-. ported'in a T-slot 54 on the front edge of the table II. The reversing lever 501s opejratlvely 55 connected to actuate the reversing valve in the control valve 49 to reverse the direction of movement of the table II.

A second control lever 69 is pivotally mounted on a stud 6| on the front of the machine base I9. The lever 69 is operatively connected to the control valve 49 and is arranged when moved toward or from the machine base I9 to stop or start the hydraulic traversing movement of the table II. A speed control knob 62 which moves with the lever 69 is operatively connected to regulate a speed control or throttle valve contained within the valve 49 so as to control the table speed. The details of'the valve 49 and the connection of the control levers 59 and 69 therewith have not been illustrated, since this mechanismis identical with that shown in my prior United States Patent No.2,071,677, to which reference may be had for details of disclosure not contained herein.

A wheel feeding mechanism is provided for manually feeding the grinding wheel I9 toward and from the work I6, which comprises a half nut' 65 depending from the wheel slide 29. The half nut 65 meshes-with a rotatable cross feed screw 66 which is slidably keyed to a rotatable sleeve 61. The rotatable sleeve 61 is supported in a bearing 68 in the base I9 and carries at its other end a gear 69. The gear 69 meshes with a pinion I9 formed on the inner end of a rotatable shaft II which is journalled in bearings I2 and I3, respectively, in the base I9. A manually operable feed wheel I5 is mounted on the fogward end of a stud I6. The feed wheel I5 carries a pinion "I"! which meshes with a gear 18 rotat ably supported on a stud I9. A gear 89 is formed integral with gear 18 and meshes with a gear 8| keyed on the outer end of the shaft I I, so that a manual rotation of the feed wheel I5 serves to rotate the feed screw 66 in either direction to cause a forward ,or rearward feeding movement of the grinding wheel I9 and the wheel slide 29.

The-feed wheel I5 may be provided with the usual well known micrometer adjusting mechanism 82 which is substantially identical with that shown in the expired U. S. patent to Norton No. 762,838 dated June 14, 1904. This micrometer mechanism serves precisely to adjust the stop on the manual infeed to permit a compensation forwheel wear.

. In the preferred construction, the wheel slide 29 is arranged so that it may be moved toward and from the work piece I6 to grind the same to a predetermined size by means of a fluid pressure actuated feeding mechanism which may be of the type shown in my prior Patent No. 2,082,728. As illustrated, the rear end of the feed screw 66 is rotatably supported in a slidably keyed bearing 88 which is supported in a casing 86 on the base I9 of the machine. A fluid pressure cylinder 81 is attached to the casing 86 and contains a slidably mounted piston 88 which is connected by a piston rod 89 with thev bearing member. 85 and is arranged so that when fluid is admitted under pressure to a cylinder chamber 99, the piston 88 will be moved into its rearward position (Fig. 2), transmitting a corresponding movement through the feed screw 66, the half nut 65, to move the wheel slide 29 and the grinding wheel I9 rearwardly to an inoperative position. T

Similarly, when fluid under 'pressure is admitted to a cylinder chamber 9|, the wheel'slide 29 and grinding wheel I9 are caused to move in a forward directioiitomove the grinding wheel toward the crankshaft I6 for a grinding operation. When fluid is admitted either to the cylinder chamber 99 or the cylinder chamber 9|, a rapid approaching or receding movement of the wheel I9 and wheel slide 29 is provided.

It is desirable to provide a suitable fluid pressure controlling or feed regulating mechanism for modifying the rapid approaching movement caused by the piston 88 to obtain a controlled and predetermined feeding movement of the grinding wheel I9. In the preferred construction, a self-contained dash pot feed regulator is provided comprising a pair of dash pot cylinders 92, 93 which contain dash pot pistons 94 and 95, respectively. The dash pot pistons 94 and 95 and their respective cylinders 92 and 93 are arranged with their axes parallel to each other and spaced on diametrically opposite sides of the piston rod 89. The dash pot pistons 94 and 95 are normally held in a rearward position by means of springs. Adjustable stop screws 96 and 91 serve, respectively, to limit the rearward movement of the dash pot pistons 94 and 95.

The forward rapid feeding movement of the grinding wheel I9 and the wheel slide 29 continues until an adjustable sleeve 98, which is adjustably supported on the rear portion of the piston rod 39, engages the ends of the dash pot pistons 94 and 95, respectively, after which the rapid approaching movement of the grinding wheel I9 and the wheel slide 29, as produced by the piston 88, is reduced to a slower predetermined grinding feed due to the fact that fluid confined within the dash pot cylinders 92 and 93, which are interconnected, exhausts through a passage 99, a needle valve I99, into a reservoir I9I contained with the dash pot casing. By ad- -justing the aperture of the needle valve I99, a

desired and predetermined infeed may be obtained.

When fluid under pressure is admitted to the cylinder chamber 99 to cause a rearward movement of the piston 88, the sleeve 98 moves rearwardly and the released compression of the springs within the dash pot cylinders 92 and 93 serves to return the dash pot pistons 94 and 95, respectively, to the rearward position, as illustrated in Fig. 2. During the rearward movement of the dash pot pistons 94 and 95, a suction is created within the dash pot cylinder chambers 92 and 93, respectively, which serves to aid in drawing fluid from the reservoir I9I, through a pipe I92, and a ball check valve I93, to fill the dash pot cylinder chambers 92 and 93 for the next infeeding operation. During the infeeding movement of the dash pot pistons 94 and 95, fluid within the dash pot cylinders 92 and 93 serves to hold the ball check valve I93 closed so that fluid within the dash pot cylinder chambers sired, but for the sake of simplicity of illustra-,

tion, the fluid under pressure from the pump 31 is utilized to operate the wheel feeding mechanism. Fluid under pressure from the pump 31 is forced through the pipe 38 and a pipe I94, to

. a control valve I95. The control valve I95 is of a balanced piston type comprising a valve stem I96 having formed integral therewith valve pis tons I91, I98, I99 and II9.

, 2.11:1,217 In the position of parts as iliustratedIthe valve stem I88 is in" its rearward position so that fluid 'under pressure passing through the-pipe I84 enters a valve chamber between the valve pistons I88 and I88 and passes through" a passage III into cylinder chamber 88, to move the piston 88 rearwardly to withdraw the wheel slide 28 and the grindingwheel I 8 from operative engagement with the crankshaft I6. Duringthis movement, fluid is exhausted from the cylinder chamber 8I, through a'passage' II2, through a valve chamber located between the valve pistons I81 and I88, and through a pipe II3 which exhaustsinto the reservoir 35.

The valve stem I86 is shifted into the reverse position, that is, it is moved forward or toward the left (Fig. 2), so that fluid under pressure passing through thepipe I84 and the valve chamber between the valve pistons I88 and I88 misses through the passage I I I, into a valvechamber between the valvepistons I 88- and H8, respectively, and out throughv the pipe II3 into the reservoir 35.

The infeeding movement of the grinding wheel I8 under the control of thepiston 88 continuesat a rapid rate until the sleeve 88 picks up the dash pot pistons 84 and 85 to reduce the approaching movement .of the grinding wheel I8 to a slow predetermined grinding feed which continuesuntil an adjustable stop sleeve II5, which is in turn supported onlthe piston rod 88, engages a stop surface III; on .the end of the dash pot casing, thereby positively limiting or stopping the forsition thereon by means of a lock nut. The stop sleeve H5 is mounted on the periphery of the sleeve 88 and is arranged to be locked in ad- ;justed position thereon by lock nuts.

-I'he headstock I4 is preferably a motor driven headstock in which'an electric motor I28 'is -mounted on the upper part of the headstock.

headstock shown in the U. S. patent to Belden No. 1,631,458 dated June '7,-1927, to which reference may had for amore detaileddisclosure of the driving mechanism for the headstock. The face plate I carries the usual driving pm which engages an aperture or recess in the end of the crankshaft or work piece .IIi being ground to rotate the same.

The crankshaft or other similar .work I5 to be ground. is of considerable weight facilitate operatio'n of the machine and-obtain the maximum production therefrom, it is desirable, to provide a'suitable mechanism for abrupt- 1y stopping the rotation of the-face plate I25 of 3 the headstock I4 and work piece after the grinding operation has been completed. In the preferred form of construction, the headstock motor- I28 is of the reversible type which is controlledby magnetic reverse starter [switch I28, and a motor brake switch I21 is mounted on top of the motor I28. In the electrical diagram" (Fig. 3). the electric motor I28 is provided with two fields which arecontrolied by the magnetic starter reverse switch I28 which throws the forward end field of the motor I28 into operation. When a control lever to be hereinafterdescribed is shifted to stop the work rotation at the end of agrinding operation,- a normally open limit switch I28 is closed bymovement of a control lever,

which serves to complete the circuit in the power lines through the motor brake switch I21 "and through the starter reverse switch' I28 which serves to actuate a magnetic reverse starter switch I38 which serves instantaneously to reverse the current in the motor I28 and thereby instantaneously to stop the rotation of the motor I28 and the headstock face plate I25, thus reducing the of work I8 and the next.

The table I I may be traversed longitudinally by means of a-manually operable traverse mechanism comprising a hand wheel I which is ,mounted on the outer end of a rotatable shaft I38. The shaft I38 carries at its inner end a gear I31 which meshes with a gear I38. The gear I38 is rotatably supported on a shaft or stud I38. A gear I48 is also rotatably mounted on the shaft I38 and is fixedly \connected to rotate with the gear I38. The gear 148 meshes with a gear I mounted onthe outer end of a rotatable shaft I42. carries a pinion I43 which meshes with a rack bar I44 depending from the under side of the table II. It will be readily apparent from this disclosure that rotation of the hand wheel I35 The inner end of the shaft I42 will transmit a longitudinal traversing movement the bearings of the shaft I6, it is desirable to provide an interlocked relationship between the work rotation and the wheel feed so th after the grinding operation has been completed, the wheel slide 28- must be withdrawn so that the 1 -grinding wheel I8 is out of contact with the fln-.

ish ground portionof the workpiece I8 before the workrotation may be stopped. 'I'his is' preferably accomplished by providing a manually operable control lever I45 which is arranged so that it maycontrol both the work rotation-and the infeeding movement 'of the grinding wheel I8..

Thecontrol lever-I45 is supported within 9. casing I 46. The lever I45 is preferably mounted in a gimbal joint so that it is free to be moved in any direction. As illustrated in Fig. 3;- the lever- I45 is pivotally supported on astud I41. Thestud I41 issuppOi-tdby a; ring-shaped member I48. Ili' ring-shaped member I48 is-in turn supported by the opposed studs I48 and I58 which are supported inthe casing I48.

It will be readily apparent from the disclosure in the upper portion of F g. 3 thatthe lever I45 may not only be moved about the axis ofthe stud .m but may also be moved about the axis of the studs I49 and I59 or may be moved in a combined path, thus forming a universal joint control lever I45-is moved in a counterclockwise direction (Fig. 3), the lug I52 engages the pin I53 and moves it toward the right. This movement serves to rock the control lever I54 of the 7 wheel I9 has movedrearwardly outof contact. with the work piece I6 being ground, asuitable latch mechanism is provided .comprising a stud limit switch I29 to close the circuit. The closing of the limit switch I29 operates in a manner above described to start the rotation of the work drive motor I 29.

In order to interlock the work rotation control with the wheel feed mechanism, a downwardly projecting lever I51 is formedintegral with the ring-shaped member I48. The lever I51 is con nected at its lower end by a stud I58 with a link I59. The other end of the link' I59 is connected by a stud I 69 with a rock arm I'6I pivotally sup- .ported on a stud I62 which is in turn supported on an upwardly projecting bracket I63. The upper end of the rock arm I6I is provided with an elongated slot I64 within which a pin I65 may slide. downwardly projecting lugfixedly fastened to-the valve stem I96. When the control lever I45 is moved away from the operator into the position illustrated in Fig. 2, this motion will be transmitted through the link I59, the rock arm I6I, to

move the valve stem I96 toward the right (Fig. 2) to position the valve pistons, as illustrated in Fig. 2, so as to admit fluid under pressurethrough the control valve I 95 to the cylinder chamber 99 to cause a rearward movement of the grinding wheel I9. Similarly, when the control lever I45 ismoved toward the operator (Fig. 2), this motion will be transmitted through the link I59, the

rock arm I6\I,-to move the valve stem .I96 toward the left (Fig. 2) to shift the valve pistons so that fluid under'pressure passing through the control valve I95 will be admitted through passage II2 into the cylinder chamber 9| to cause a forward approaching movement of the grinding wheel I9.

In order to interlock the'work rotation with the wheel feeding mechanism so that the work rotation cannot be stopped until the grinding I66 which depends fromthe lower surface of the lever II. -A pivdtally mounted latch member I61 supported on a stud I68 is normally held in the full line position (Fig. 5) by means of a spring I69 which tends to rock the latch member I61 in a clockwise direction so that the short arml19 engages a stop screw I 1I adjustably mounted within the-casing I46. When the lever I45 is in the position illustrated in Fig. .4; it may be swung in a direction parallel with the table I I without.

affecting the latch mechanism. When the lever H5 is moved in a clockwise direction (Fig. 4),

the lower arm I5I which carries thestud I66 moves'into position I5Ia and the stud into position I66a, thereby depressing the latch I61 into the dotted line position I 61a .(Fig. '5). In this position of the parts, when the lever I45 is moved The-pin I65 is fixedly mounted on the parallel to'the table I I, the pin I 66 rides across the upper; face-of the spring-pressed latch I61 until the pin I66 pass& over the edge of the latch I 61 into position I66b (Fig. 6) whereupon the released compression-of the spring I69 returns the latch I61 from position I61a into the full line position, thus locking the lever I45 in dotted line position I450 (Fig, 3) and holding the limit switch I29 closed. This latch permits the lever I45 to be moved toward and from the operator to cause an approaching or receding movement of the grinding wheel I9, but prevents a movement of the lever I45 longitudinally of the machine to stop the work rotation when the grinding wheel I9lis in its forward grinding position. Y

The operating positions of the lever I45 are .shown diagrammatically in Fig- '7. JVhen the lever I45 is in the position I45c, the work rotation is stopped and the wheel slide 29 is in its rearward position to permit unloading the finish "ground-work piece I6 and inserting a new work piece there instead. When the lever I45 is'shifted from position 50 into position 511, this transmits a movement through the link I59 and rock arm I6I to'shift the valve stem I96 so as to cause thework piece I6. During this forward approaching movement of the grinding wheel I9, the work rotation is preferably stopped so that the operator'may readily observe the position of the grinding wheel I9 relative to the portion of the work ,I6 to be ground and, if necessary, longitudinally move the table II by means of the hand wheel I35 to bringthe work piece I6 into. the desired relationship with the grinding wheel the grinding wheel I9 to move forward toward I9 before starting the rotation of the work piece I6. After the work piece I6 has been located as desired, the control lever I45 may then be shifted into position I45a (Fig. '1) which serves to close the limit switch I29 and thereby start the'rotation of the work piece I6.

In the work rotating position I45a (Fig. 7.) ,the

latch pin I66 is in a latched position I66b (Fig.

6) In this position of the parts, the control lever I45 cannot be shifted from position I45a into position I45d since the latch pin I66 rides on the side of the latch I61 and prevents such movement. The only direction in which the lever I45 may be moved is in a direction toward position I45b 59 (Fig. '7) which serves through the connecting link I59 and rock arm I6I to shift the valve stem I96 and the control valve I95 into the full line position as shown in Fig. 2 to start a rearward movement of the grinding'wheel I9. When the lever -I45 has been moved toward position 51) through a sufiicient extent so'that latch pin I66 swings so that it clears the inclined portion of the latch 161, the released compression of a spring I12 serves to rock the lever I45 in a clockwise direction -(Fig. 3) so that thelever I45 assumes the full line position illustrated in Fig. 3.

It will be, apparent from the-foregoing disclosure that in starting a grinding operation on a portion of the crankshaft I6to'be ground, either the work I6 or the grinding wheel I9 may be moved first, as desired, but that in stopping the machine, it is necessary first to shift the control lever I45 to withdraw the grinding wheel I9 from operative contact with the work-I6 before the work rotation canbe stopped, thus preventing the grinding of aflat on the surface of the work I6 beingground. v H

It is desirable to provide a safety control where.-

by the grinding wheel I9 may be started in a rearward movement and the work rotation automatically stopped in case the machine fails to.

machine within easy reach of the operator.

- push button I15 is normally open and is connected'in series with a solenoid I which is preferably of the push type. Armature I" of the solenoid I16 is connected by a stud with an outwardly extendingprojection of the valve stem I06. If it is desired quickly to stop the grinding cycle,-the operator presses the button I15.to close the circuit. and energize the solenoid I16 which pushes the valve stem I66 toward the right (Fig.

2) into the full line position shown which serves to admit .fluid under pressure to the cylinder chamber Stand thereby initiate a rearward movement of the grindingwheel I9. The movement of the -valve stem I06 toward the right (Fig.

, 2') 'by the solenoid I16 serves to rock the lever thereby stopthe rotation of the. work drive The operation of this mechanism will be readily apparent from the foregoing disclosure. A work.

piece, such as a crankshaft I6', is mounted on the machine on headstock center l1 and footstock center I8. The table II is then traversed longitudinally eitherby the fluid pressure mechanism above described or manually by rotation of the hand wheel I to position the crankshaft I61 relative to the grinding wheel IS. The control lever I45. is then preferably shifted from position I450 into theposition H511 to cause a forward" I versely movable rotatable grinding wheeLmeans approaching movement of the grinding wheel I9 while the work I6 is stationary, thus permitting the operator to observe the relative positionof the crankshaft I6 to the operative face of the wheel I8 and, if necessary, permitting a manual adjustment of the table I I before the grinding wheel 19 reaches a grinding position.

a After the operator is satisfied that the crankshaft is properly located relative to the wheel I 5, the lever I45 may be shifted from position I45d into position so, which serves to close the limit switch I29 andthereby start the rotation of-thecrankshaft I6 for a grinding operation. The

grinding operation continues until the portion of operable feeding mechanism may be utilized, if

desired, or in the-preferred form of operation of t e machine the power operated, hydraulically driven mechanism. may be utilized to feed the grinding wheels to grind the work to a predetermined size. The machine may be equipped with the well known dial indicator (not shown) suspended from a portion of themachine so that the operator may visibly watch the reduction in size of the workpiece. When the dial indicator indicates that'the work-f has been ground"to the required size, the push button I15 is actuated, which operates in the manner above described first to cause a separating movement of the grinding wheel relative to the portion of the crankshaft I6 being ground, and then a stopping of the work rotation after the grinding wheel I9 has receded from engagement with the portion of the crankshaft being ground. The push button I15 also serves in case of emergency quickly to stop the grinding'operation by returning the wheels to their rearward position and stopping the rotation of the crankshaft.

If desired, the receding movement of the grinding wheel I9 and the stopping of the rotation of the crankshaft I6 may be controlled by the manually operable control lever I45. The control lever I45 is-shifted manually from position l45a to position I45b which serves to start the'reare ward movement of the grinding wheel I9 to separate the wheel from the work while the work is rotating. When the lever I45 is in position I451), so that the latch pin I66 is in position I660 (Fig.

- 5) out of engagement with the side face of. the,

I latch I 61; the lever I45 may'then be shifted manually or automatically under the released compression of the spring I12 into position I'45c to,stop the work rotation so as to facilitate removal of the finish ground crankshaft I6 and the loading of a new crankshaft in the machine' I It will thus be seen that there has been -pro-' vided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all

without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown'in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim: v

1. In a crankshaft grinding machine, a'transincluding a fluid pressure piston and cylinder to move said wheel transversely in either direction, a control valve to control the admission of fluid to said cylinder, a rotatable work support including a headstock and a. footstock', means including an 7 electric motor to drive said headstock, a switch to start said motor, a main control-lever which is operatively connected when moved in one direction to actuate said switch to rotate said headstockand when moved in a. second direction to l actuate said control valve to'cause a forward or, rearward movement of the grinding wheel, and means including .a latch to hold'said lever in a position to maintain said switch closed during the in'feeding movement of the grinding wheel,

said parts being arranged to prevent stopping'of said motor except when said 'wheel has moved rearwardly out of operative engagement with'the work piece.

2. In a crankshaft grinding machine, a-transversely movable rotatable grinding wheel, means including a fluid pressure piston and cylinder to move said wheel transversely in either direction, a control valve operatively connected with said cylinder and arranged to control the" admission and exhaust of fluid therefrom, means including a solenoid to actuate said valve to cause a rearward movement ot .thegrinding h wheel,.a rotatable worksuppoift including a-hea d' stock and a"footstock, means includingan eleci- 7 trlcmotor to drive said headstock, ,a main control lever which is operatively connected to actuate said switch when moved in one direction to stop or start said motor and to shift said control 5 valve to cause either a forward or rearward movement of the grinding wheel when moved in another direction, and means including a latch associated with said lever and arranged to hold port including a motor driven headstock and a footstock, means including an electric switch to. control said motor, a pivotally mounted main control lever, operative connections between said lever and switch whereby movement of said lever I in one direction serves to actuate said switch 2 to control rotation of said work support, operative connections between said lever and control valve whereby the valve is shifted to cause either a forward or rearward feeding movement of the grinding wheel when the lever is moved in 30 a second direction, and means including a latch mechanism which is arranged to hold the control lever to maintain said switch in a closed position during the grinding operation, said latch being arranged to permit free movement of the'control lever in' a direction to control the movement of the grinding wheel 4, In a crankshaft grinding machine, a transversely movable rotatable grinding wheel, means including a fluid ,pressure piston and cylinder to 0 move said wheel transversely toward and from a crankshaft to be ground, a control valve therefor, a solenoid to actuate said valve in one direction, a rotatable work support including a motor driven headstock and a rootstock, means including an electric switch to control, said motor, a

, pivotally mounted main control lever, operative connections between said lever and switch whereby movement of said lever in one direction serves to actuate said-switch to control rotation of said work support, operative connections between said leverand control valve whereby the valve is shifted to cause either a-forward or rearward feeding movement of the grinding wheel when the lever is moved in a second direction, a latch.

to hold the control lever in position to hold said switch closedafter the work rotation has been started until the grinding wheel is moved out of engagement with the workpiece, and means including a push button to energize said solenoid to cause a rearward movement of the wheel and to release said latch and stop the headstock rotation. V

5. In a crankshaft grinding machine, a transversely movable rotatable grinding wheel, means including a fluid pressure piston and cylinder to move said wheel transversely in either direction, a control valve therefor, means includinga solenoid to actuate said valve so as to cause a rear ward movement of the grinding wheel, a rotatable work support including' a motor driven headstock and a footstock, means including an electric switch to coritrol said headstock motor, a pivotally mounted main control lever, operative connections between said motor and said switch whereby the headstockmotor is started or stopped when the lever is moved in one direction, a spring normally to hold said lever in position so that the headstock motor is stopped, connections between said control lever and said valve whereby the grinding wheel is caused to move either in. a-

forward direction or rearward direction, means including a latch associated with said lever and arranged to hold said switch closed-to rotate the work during the grinding operation, and means including a. push button whichv is operatively connected to energize 'said solenoid so as to shift .the valve and cause a rearward movement of the grinding wheel, said parts being arranged so that when the grinding wheel has-receded in a rearward direction to a predetermined extent, the latch automatically releases the control lever and the released compression, of a spring serves automatically to shift said lever and open said switch t6 stop the work rotation.

WALLACE H; WOOD. 

